Answer:
The Vikings undertook extensive trade and built a trade network that eventually covered all of modern Europe, Russia, the Middle East, Northern India, and even China. ... This led to the creation of international markets and trading across the "known world" of the time.
Explanation:
Woman in both civilizations were expected to serve men.
It was the "production of corn" that played an important role in pre-Columbian Mesoamerican civilizations. Many of these people lacked other domesticated plants.
<span />
The correct answer is option D. "Companies replaced hand-operated brakes with air brakes on trains". The development of air brakes on trains was a significant improvement of railroad safety. Air brakes function much more faster than hand-operated brakes, because hand-operated brakes required that the brakemen turned the brakes in one car and jump to the next to set the brakes on, and so on.
